230
FXUS63 KBIS 162354
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
654 PM CDT Wed Jul 16 2025

.KEY MESSAGES...

- Areas of wildfire smoke may return to parts of western North
  Dakota this evening through tonight.

- Well below average temperatures through Thursday, with lows
  tonight in the 40s and highs on Thursday in the mid 60s to mid
  70s.

- Medium chances for showers and thunderstorms Thursday night
  through Friday, and again Saturday night through Sunday. A few
  strong to severe storms are possible Thursday night.

&&

.UPDATE...
Issued at 652 PM CDT Wed Jul 16 2025

Light rain has exited our forecast area, and dry weather is now
expected through tonight. Throughout the day tomorrow, CAMs
continue to show a NW-SE band of scattered light showers moving
from southwest to northeast across the western half of the
state. Deterministic guidance shows modest low level warm air
advection and a deep layer of mid level isentropic ascent. The
near-surace layer will remain dry, but forecast ceilings lower
to near 5,000 ft. Given this signal has been consistent, a 15 to
20 percent chance of showers has been added to the forecast
tomorrow morning and afternoon. No thunder is expected, and
maximum QPF is not anticipated to exceed a couple hundredths of
an inch.

Satellite and surface observations show higher concentrations of
smoke filling in across parts of western and central North
Dakota, but near-surface impacts appear spatially inconsistent
and not exactly in line with modeled smoke output. The mention
of smoke in the forecast has been expanded spatially but reduced
from areas of to patchy for this update.

&&

.DISCUSSION...
Issued at 325 PM CDT Wed Jul 16 2025

This afternoon, broad surface high pressure was centered across
the southern Canadian Prairies and into northwest North Dakota,
underneath a shallow trough embedded in longwave troughing
extending across much of the CONUS. A few embedded vort maxes
have been rotating through the trough base, leading to on and
off rain across the southern part of the forecast area. At this
point, rain is primarily limited to the far south central and
southeast, with no additional development expected for the rest
of the afternoon and evening.

Clouds are expected to diminish through the evening as the high
pressure drifts southeast, with seasonably chilly lows tonight.
Current forecast has widespread 40s tonight, but can`t rule out
the typical cold spots (Hettinger to Glen Ullin corridor)
dropping into the upper 30s, with the latest NBM giving this a
roughly 20 percent chance of occurrence.

Synoptic flow becomes more zonal on Thursday, with a few CAMs
showing some very light morning rain showers in the southwest,
although opted to keep forecast dry at this point. Temperatures
begin a slow warming trend, with highs in the mid 60s to lower
70s and a bit of a southeast breeze during the day. Another
embedded trough is progged to drop south through the area later
Thursday night, with long-range CAMs beginning to advertise
scattered convection on the nose of a low-level jet. Midday
update did add in mention of isolate severe thunderstorms across
parts of the west and into the south central, with main hazards
of hail up to the size of ping pong balls and wind gusts up to
60 mph. There is quite a lot of bulk shear being advertised, on
the order of 60 knots, although instability is marginal at best,
generally under 1000 J/kg. HREF does paint some UH tracks
starting in the late evening and continuing through part of the
overnight hours.

That surface trough will get washed out quickly on Friday, as
precipitation chances diminish through the afternoon and
evening. Friday evening and much of Saturday should be dry in
between waves, with highs on Saturday in the mid 70s to lower
80s. A shallow ridge will be building in through the day
Saturday, just downstream of a trough and closed low moving over
British Columbia and Alberta. As the low approaches,
precipitation chances start Saturday night, with machine
learning guidance beginning to advertise increasing potential
for severe weather across western North Dakota. Things bump up
further on Sunday as longer lead deterministic guidance has a
swath of sufficient buoyancy and bulk shear to support severe
convection, mirrored in higher probabilities in machine learning
guidance across much of the state. This trend continues through
the start of the work week, as the original trough gets washed
out but a secondary one digs over the Pacific Northwest, leading
to southwest flow aloft across the Dakotas, a favorable pattern
for severe storms across our area. High temperatures during
this period are forecast generally in the 80s, with low chances
of exceeding 90 degrees across the south Sunday and Monday.

By the time we get to the middle of next week, cluster analysis
reveals some modest differences in the placement of the ridge axis,
which will influence the flow pattern over the Dakotas. Extended
severe weather probabilities still keep some modest chances across
the state through the end of next week, with NBM temperature
percentiles advertising a bit of a cooldown late week before warming
up next weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 652 PM CDT Wed Jul 16 2025

VFR conditions are generally expected through the forecast
period, with a couple possible exceptions. Southwest North
Dakota could see a period of MVFR ceilings Thursday morning,
but this is not expected to reach KDIK. Areas of smoke are also
returning to the region. Most of this smoke should remain aloft,
but some areas could experience visibility reductions as low as
MVFR levels at times. Scattered light rain showers could
develop in southwest North Dakota Thursday morning and expand
north and eastward through the afternoon, but no impacts to
aviation are expected. Light and variable winds overnight will
become southeasterly on Thursday at around 10 kts in central
North Dakota and 15-20 kts in the west.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Hollan
DISCUSSION...Jones
AVIATION...Hollan